1. Field of the Invention
The present invention relates to a magnetic recording/reproduction apparatus, and more particularly, relates to a magnetic recording/reproduction apparatus provided with a mechanism for moving a sub-chassis relative to a main chassis.
2. Description of the Related Art
An example of conventional magnetic recording/reproduction apparatus is disclosed in Japanese Patent Gazette No. 2627465. Referring to FIGS. 36 to 39, a conventional magnetic recording/reproduction apparatus 300 will be described.
Referring to FIG. 38, the reference numeral 301 denotes a slide chassis into which a cassette is inserted, and the reference numeral 351 denotes a main chassis. Loading lever pins 311A and 311B extend from the main chassis 351. Loading arms 303A and 303B are swingably mounted on the slide chassis 301 via a shaft. First guide bases 313A and 313B and second guide bases 315A and 315B are provided with respective tape drawing posts for drawing a tape from the cassette and allowing the tape to pass around a rotary head cylinder. The first guide bases 313A and 313B and the second guide bases 315A and 315B are driven by the loading arms 303A and 303B, respectively, to move between respective positions in a cassette mouth 322 and respective loading completion positions so as to draw out the tape from the cassette and allow the tape to pass around the rotary head cylinder.
The operation of the above components will be described.
Referring to FIG. 38, after the insertion of the cassette, the slide chassis 301 starts moving in the direction indicated by arrow B3 to reach the position shown in FIG. 39. During this movement, the loading arms 303A and 303B have not yet begun to swing.
In the above state, the loading lever pins 311A and 311B (FIG. 39) on the main chassis 351 engage with hook portions 309A and 309B of the loading arms 303A and 303B, respectively, which move in synchronization with the movement of the slide chassis 301. As the slide chassis 301 moves further in the direction B3, the loading arms 303A and 303B are driven by the loading lever pins 311A and 311B to begin swinging in the directions indicated by arrows J and K, respectively. By this swinging of the loading arms 303A and 303B, the first guide bases 313A and 313B and the second guide bases 315A and 315B start moving in the direction B3, and reach to the respective loading completion positions as the slide chassis 301 moves in the direction B3, thereby allowing the tape to pass around the rotary head cylinder for a predetermined arc.
The conventional apparatus with the above construction has at least the following design problem.
As described above, the loading arms 303A and 303B are constructed to be driven by and moved in synchronization with the movement of the slide chassis 301. Therefore, the respective components cannot be moved independently.
For example, it is impossible to construct the apparatus 300 so that the swinging of the loading arms 303A and 303B is started before the start of the movement of the slide chassis 301 to enable the guide bases 313A, 313B, 315A, and 315B to protrude from the cassette mouth 322 so that the guide bases 313A, 313B, 315A, and 315B can pass through a space between the rotary head cylinder and the cassette during the time when the space is sufficiently large before it is reduced by the movement of the slide chassis 301 in the direction B3. Accordingly, in the above construction, it is necessary that the cassette starts moving from a position sufficiently away from the rotary head cylinder so that the space between the rotary head cylinder and the cassette is guaranteed as sufficient when the guide bases 313A, 313B, 315A, and 315B pass through the space. This requires the slide chassis 301 to undergo a large amount of the movement.
The above construction greatly restricts the design of the mechanism. For example, guide grooves 343A, 343B, 343C, 343D formed on the slide chassis 301 (FIG. 36) need to be made long, which decreases the strength of the slide chassis 301. Also, the amount of movement of a slide chassis driving lever 359 (FIG. 37) for driving the slide chassis 301 becomes large. This in turn increases the lift amount of a cam groove 357 formed on a main cam 353 for driving the slide chassis driving lever 359. As a result, the diameter of the main cam 353 increases, and thus realization of a small-sized mechanism is not possible. Apart from the above construction, if the guide bases 313A, 313B, 315A, and 315B are to be driven by separate driving means without synchronization with the slide chassis 301, two separate driving means are required, which also frustrates the realization of a small-sized mechanism.
The object of the present invention is to provide a magnetic recording/reproduction apparatus provided with a small-sized mechanism capable of achieving high reliability.